Expandable intervertebral implant

ABSTRACT

A method of inserting an expandable intervertebral implant is disclosed. The implant preferably includes first and second members capable of being expanded upon movement of first and second wedges. The first and second wedges, while being capable of moving with respect to each other and the first and second members are also preferably attached to the first and second members. In addition, the first and second wedges are preferably capable of moving only in a first direction, while movement in a second direction is inhibited. The first and second wedges are also preferably prevented from torsionally moving with respect to the first and second members.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 13/562,634 filed Jul. 31, 2012 which is a divisionalapplication of U.S. patent application Ser. No. 12/072,912, filed Feb.28, 2008, the disclosures of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Surgeons are performing more and more spinal surgeries to correctdifferent spinal defects in the hopes of reducing pain and restoringnormal or close to normal movement. One area of particular interest liesin the restoration of normal spacing between adjacent vertebral bodies.Whether due to the degeneration of the intervertebral disc over time orbecause of an injury, a decrease in spacing between vertebral bodies cancause a myriad of problems for a patient, the least of which is painresulting from the pinching of nerves between the bodies. Correctingthis problem is often very important to returning a patient to his orher normal level of activity and/or managing the pain associated with adegenerative spinal problem.

Over the years, there have been many different techniques employed inrestoring the normal disc space. For instance, solid fusion devices havebeen implanted in many patients in the hopes of both restoring normaldisc spacing and preventing further degeneration of the space by fusingthe vertebral bodies to one another. Recently, there has been a trend toboth restore the disc spacing and allow natural movement of the adjacentvertebral bodies with respect to one another. Nonetheless, there existcertain extreme cases of degradation of the disc space which requireextreme measures in order to restore the natural spacing.

Often, the decrease in spacing will be so drastic that some amount ofdistraction of the adjacent vertebral bodies will be required. Althoughthis distraction is sometimes achieved through the use of various tools,the desire for faster and more efficient surgical techniques favors theelimination of superfluous surgical steps. Thus, there exists a need foran intervertebral implant which is implantable in an unexpanded stateand easily expandable to restore the disc space, thereby negating theneed for additional tools and the additional surgical steps of usingthem.

BRIEF SUMMARY OF THE INVENTION

A first aspect of the present invention is an expandable implant forimplantation between two vertebral bodies. In a first embodiment of thisfirst aspect, the implant includes a first member, the first memberincluding a first vertebral contact surface and a first interiorsurface, a second member, the second member including a second vertebralcontact surface and a second interior surface, the first and secondinterior surfaces facing towards one another, a strut attached to boththe first and second members, and a wedge disposed between the first andsecond interior surfaces and attached to at least one of the first orsecond members. Preferably, in this embodiment, movement of the wedge ina first direction causes movement of at least one of the first or secondmembers in a second direction.

In other embodiments of the first aspect, the wedge may be attached toat least one of the first or second members by a deformable tether. Theimplant may include first and second wedges, where movement of the firstand second wedges towards one another causes an increase in a distancebetween the first and second interior surfaces. The first and secondwedges may each be attached to both of the first and second members by adeformable tether. Additionally, one of the first or second wedges mayinclude a bulleted or rounded surface for aiding in insertion of theexpandable implant between the two vertebral bodies. Further, the firstwedge may include first and second angled wedge surfaces for cooperatingwith first and second angled interior surfaces of the first and secondmembers respectively, the second wedge may include third and fourthangled wedge surfaces for cooperating with third and fourth angledinterior surfaces of the first and second members respectively, andmovement of the first and second wedges towards one another may bepermitted, while movement of the first and second wedges away from oneanother is prevented. This may be the case because the first, second,third, and fourth wedge surfaces and the first, second, third, andfourth interior surfaces may each include teeth. The first and secondmembers and the first and second wedges may also cooperate to define atleast one aperture through the implant adapted for bone growththerethrough.

A second aspect the present invention may be another expandable implantfor implantation between two vertebral bodies. In one embodimentaccording to this second aspect, the implant may include a first member,the first member including a first vertebral contact surface and a firstinterior surface, a second member, the second member including a secondvertebral contact surface and a second interior surface, the first andsecond interior surfaces facing towards one another, a strut attached toboth the first and second members, and first and second wedges disposedbetween the first and second interior surfaces, one of the first orsecond wedges including a bulleted or rounded surface for aiding ininsertion of the expandable implant between the two vertebral bodies.Preferably, in this embodiment, movement of the first wedge towards thesecond wedge causes an increase in a distance between the first andsecond interior surfaces.

In other embodiments of the second aspect, each of the first and secondwedges is attached to each of the first and second members by deformabletethers. The first wedge may include first and second angled wedgesurfaces for cooperating with first and second angled interior surfacesof the first and second members respectively, the second wedge mayinclude third and fourth angled wedge surfaces for cooperating withthird and fourth angled interior surfaces of the first and secondmembers respectively, and movement of the first and second wedgestowards one another may be permitted, while movement of the first andsecond wedges away from one another is prevented. This may be the casebecause the first, second, third, and fourth wedge surfaces and thefirst, second, third, and fourth interior surfaces each include teeth.Furthermore, the first and second members and the first and secondwedges may cooperate to define at least one aperture through the implantadapted for bone growth therethrough.

A third aspect of the present invention may be another expandableimplant for implantation between two vertebral bodies. According to oneembodiment of this third aspect, the implant may include a first member,the first member including a first vertebral contact surface and a firstinterior surface, a second member, the second member including a secondvertebral contact surface and a second interior surface, the first andsecond interior surfaces facing towards one another, a strut attached toboth the first and second members, and first and second wedges disposedbetween the first and second interior surfaces. Preferably, in thisembodiment, movement of the first wedge towards the second wedge causesan increase in a distance between the first and second interiorsurfaces, and at least one of the first and second wedges is preventedfrom torsionally moving with respect to the first and second members.

In other embodiments of the third aspect, each of the first and secondwedges may be attached to each of the first and second members bydeformable tethers. The first wedge may include first and second angledwedge surfaces for cooperating with first and second angled interiorsurfaces of the first and second members respectively, the second wedgemay include third and fourth angled wedge surfaces for cooperating withthird and fourth angled interior surfaces of the first and secondmembers respectively, and movement of the first and second wedgestowards one another may be permitted, while movement of the first andsecond wedges away from one another is prevented. This may be the casebecause the first, second, third, and fourth wedge surfaces and thefirst, second, third, and fourth interior surfaces may each includeteeth. Further, the first and second members and the first and secondwedges may cooperate to define at least one aperture through the implantadapted for bone growth therethrough. Still further, the first andsecond members may include either a depression or a protuberance, andthe first and second wedges may include the other of a depression or aprotuberance. The first and second members may include a tongue, a pin,or an elongate projection, and the first and second wedges may includeeither a groove or a channel.

A fourth aspect of the present invention is another expandable implantfor implantation between two vertebral bodies. One embodiment of thisfourth aspect includes a first member, the first member including afirst vertebral contact surface and a first interior surface having afirst and third angled interior surfaces, a second member, the secondmember including a second vertebral contact surface and a secondinterior surface having second and fourth angled interior surfaces, thefirst and second interior surfaces facing towards one another, a strutattached to both the first and second members, a first wedge disposedbetween the first and second interior surfaces, the first wedgeincluding first and second angled wedge surfaces for cooperating withthe first and second angled interior surfaces of the first and secondmembers respectively, and a second wedge disposed between the first andsecond interior surfaces, the second wedge including third and fourthangled wedge surfaces for cooperating with the third and fourth angledinterior surface of the first and second members respectively.Preferably, in this embodiment, movement of the first wedge towards thesecond wedge causes an increase in a distance between the first andsecond interior surfaces, and movement of the first and second wedgestowards one another may be permitted, while movement of the first andsecond wedges away from one another is prevented.

In other embodiments of the fourth aspect, the first, second, third, andfourth wedge surfaces and the first, second, third, and fourth interiorsurfaces may each include teeth. Furthermore, the first and secondmembers and the first and second wedges may cooperate to define at leastone aperture through the implant adapted for bone growth there through.

A fifth aspect of the present invention is yet another expandableimplant for implantation between two vertebral bodies. In one embodimentof this fifth aspect, the implant includes a first member, the firstmember including a first vertebral contact surface and a first interiorsurface having a first and third angled interior surfaces, a secondmember, the second member including a second vertebral contact surfaceand a second interior surface having second and fourth angled interiorsurfaces, the first and second interior surfaces facing towards oneanother, a plurality of struts attached to both the first and secondmembers, a first wedge disposed between the first and second interiorsurfaces, the first wedge including first and second angled wedgesurfaces for cooperating with the first and second angled interiorsurfaces of the first and second members respectively, a first tetherconnecting the first wedge to one of the first or second members, asecond wedge disposed between the first and second interior surfaces,the second wedge including third and fourth angled wedge surfaces forcooperating with the third and fourth angled interior surface of thefirst and second members respectively, and a first tether connecting thefirst wedge to one of the first or second members. Preferably, in thisembodiment, movement of the first wedge towards the second wedge causesan increase in a distance between the first and second interiorsurfaces, and the first, second, third, and fourth wedge surfaces andthe first, second, third, and fourth interior surfaces each includeteeth. In another embodiment, one of the first or second wedges mayinclude a bulleted or rounded surface for aiding in insertion of theexpandable implant between the two vertebral bodies.

A sixth aspect of the present invention is a method of implanting anexpandable implant between two vertebral bodies. In a first embodimentof this sixth aspect, the method includes the steps of inserting theexpandable implant between two vertebral bodies, the implant having afirst member, a second member, and a wedge disposed between the firstand second members and attached to at least one of the first or secondmembers. The method also includes the step of moving the wedge in afirst direction so as to cause movement of the first and second membersin a second direction. Preferably, the moving step causes expansion ofthe first and second members which in turn causes movement of thevertebral bodies away from one another.

In other embodiments of the sixth aspect, the moving step may beperformed through the use of a deployment tool. The inserting step mayalso be performed through the use of the deployment tool. In certainembodiments, the implant may further include at least one deformablestrut and more than one wedge. Each wedge may be attached to at leastone of the first or second members by a deformable tether, or in somecases, the wedges may be attached to both members by deformable tethers.Additionally, the implant may further include structure which allows forthe movement of the at least one wedge in a first direction, butprevents movement of the wedge in an opposition direction. Furthermore,the wedge may be prevented from torsionally rotating with respect to thefirst and second members.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the subject matter of the presentinvention and the various advantages thereof can be realized byreference to the following detailed description in which reference ismade to the accompanying drawings in which:

FIG. 1 is a front perspective view of an expandable intervertebralimplant according to one embodiment of the present invention in agenerally unexpanded state.

FIG. 2 is a rear perspective view of the expandable intervertebralimplant shown in FIG. 1.

FIG. 3 is a side perspective view of the expandable intervertebralimplant shown in FIG. 1.

FIG. 4 is a top view of the expandable intervertebral implant shown inFIG. 1.

FIG. 5 is a side view of the expandable intervertebral implant shown inFIG. 1.

FIG. 6 is a front perspective view of the expandable intervertebralimplant shown in FIG. 1 in a fully expanded state.

FIG. 7 is a perspective view of an expandable intervertebral implantaccording to another embodiment of the present invention.

FIG. 8 is another perspective view of the expandable intervertebralimplant shown in FIG. 7.

FIG. 9 is a side view of the expandable intervertebral implant shown inFIG. 7 in a fully expanded state.

FIG. 10 is a perspective view of an expandable intervertebral implantaccording to another embodiment of the present invention.

FIG. 11 is another perspective view of the expandable intervertebralimplant shown in FIG. 10.

FIG. 12 is an enlarged view of a portion of the expandableintervertebral implant shown in FIG. 10.

FIG. 13 is a perspective view of an impaction instrument for use withthe expandable intervertebral implant shown in FIG. 1.

FIG. 14 is an enlarged view of a distal portion of the impactioninstrument shown in FIG. 13.

FIG. 15 is another enlarged view of the distal end of the impactioninstrument shown in FIG. 13.

FIG. 16 is a perspective view of a portion of one end of the impactioninstrument shown in FIG. 13, assembled with the expandableintervertebral implant shown in FIG. 1.

FIG. 17 is a perspective view of one end of the impaction instrumentshown in FIG. 13, fully assembled with the expandable intervertebralimplant shown in FIG. 1.

FIG. 18 is a side cross-sectional view of the assembly shown in FIG. 17.

FIG. 19 is a perspective view of the impaction instrument shown in FIG.13, fully assembled with the expandable intervertebral implant shown inFIG. 1.

FIG. 20 is a perspective view of a deployment tool coupled with theintervertebral implant shown in FIG. 1.

DETAILED DESCRIPTION

Referring to the drawings, wherein like reference numerals refer to likeelements, FIGS. 1-6 depict a first embodiment expandable intervertebralimplant, designated generally by reference numeral 10. As is shown inthe drawings, implant 10 includes, among other elements that will bediscussed below, a first member 12, a second member 14, a first wedge16, a second wedge 18, and a plurality of struts 20 a-d. Implant 10 isdesigned so that is capable of expanding from a generally unexpandedstate (shown in FIGS. 1-5) to a fully expanded state (shown in FIG. 6),as well as several different partial expended states therebetween. Thespecific details of the structure and the operation of implant 10 willbe discussed further below.

As is shown in FIGS. 1-6, first and second members 12 and 14 aregenerally planar plate-like elements capable of contacting andsupporting a portion of vertebral bodies implant 10 is inserted between.First member 12 includes a first vertebral body contacting surface 22and a first interior surface 24 having two first angled interiorsurfaces 26 a and 26 b. Likewise, second member includes a secondvertebral body contacting surface 28 and a second interior surface 30having two second angled interior surfaces 32 a and 32 b. First andsecond vertebral body contacting surfaces 22 and 28 may include boneengaging elements. For example, as is shown in FIGS. 1-6, firstvertebral body contacting surface includes projections 23 and secondvertebral body contacting surface 28 includes projections 29.Preferably, these projections are capable of biting into a portion ofthe bone of the adjacent vertebral bodies implant 10 is insertedbetween. Furthermore, first angled interior surfaces 26 a and 26 b mayinclude teeth 27 a and 27 b, respectively, while second angled interiorsurfaces 32 a and 32 b may include teeth 33 a and 33 b, respectively.Finally, first member 12 may define a first aperture 34 and secondmember 14 may define a second aperture 35 (only partially shown).

As is also shown in FIGS. 1-6, first and second wedges 16 and 18 aresomewhat triangular and include surfaces capable of cooperating with theabove-discussed first and second angled interior surfaces. Specifically,first wedge 16 includes first and second angled wedge surfaces 36 a and36 b for cooperation with first angled interior surface 26 a and secondangled interior surface 32 a, and second wedge 18 includes third andfourth angled wedge surfaces 38 a and 38 b for cooperation with firstangled interior surface 26 b and second angled interior surface 32 b.The various wedge surfaces may include similar teeth to those discussedabove in connection with first and second angled interior surfaces. Forinstance, as is best shown in FIG. 5, first and second angled wedgesurfaces 36 a and 36 b include teeth 37 a and 37 b, respectively, andthird and fourth angled wedges surfaces 38 a and 38 b include teeth 39 aand 39 b, respectively. The different cooperating teeth (i.e., 27 a and37 a, 27 b and 39 a, 33 a and 37 b, and 33 b and 39 b) preferably allowfor movement of first and second wedges 16 and 18 with respect to firstand second members 12 and 14 in one direction, but prevent it in anopposite direction. This will be discussed further below. It is to beunderstood that the wedges may exhibit any shape suitable for use inexpansion of implant 10.

First wedge 16 may further include an angled, bulleted, or roundedexterior surface for aiding in insertion of implant 10 between adjacentvertebrae. In the embodiment shown in FIGS. 1-6, first wedge 16 includesrounded exterior surfaces 40 a-d, which provides the bulleted nature ofthe exterior to the element. However, it is to be understood that angledsurfaces may also be employed to achieve essentially the samefunctionality. First wedge 16 also preferably includes a first wedgeaperture 42 (best shown in FIG. 1) formed therethrough and second wedge18 preferably includes a second wedge aperture 44 (best shown in FIG. 2)formed therethrough. Both of these additional elements are preferablyprovided for use during expansion of implant 10, as will be discussedfurther below.

Struts 20 a-d are preferably deformable so as to allow for the expansionof implant 10 upon the movement of first and second members 12 and 14away from one another. There are many different designs for suchdeformable struts that may be employed. For example, as is shown inFIGS. 1-6, struts 20 a-d are of an s-curve shape which facilitate easycompression and expansion. In addition, struts 20 a-d are preferablydesigned so that they apply tension to first and second members 12 and14 during and after expansion of implant 10. This encourages evendeployment of the device. More particularly, each of struts 20 a-20 dincorporates a specific structure designed to aid in the movement infirst and second members 12 and 14 away from one another. As is shown inFIG. 5, each of the struts (of which only struts 20 a and 20 b are shownin FIG. 5) includes at least one curved section 102, which is designedto be thicker than at least one middle section 104, such that the curvedsection 102 will deform subsequent to the deformation of middle section104. Furthermore, each strut preferably includes at least one endsection 106 that is joined to one of end plates 12 and 14. This endsection 106 is preferably designed in a thicker fashion, such that thereis no deformation at this point at anytime during the entire expansionsequence. Thus, the specific configuration of struts 20 a-d facilitatesthe even deployment of implant 10 by specifically providing a structurethat allows for a predetermined and consistent expansion sequence.

First and second wedges 16 and 18 are each respectively attached to bothfirst and second members 12 and 14. As is shown in FIGS. 1-6, firstwedge 16 is attached to first member 12 through the use of tethers 46 aand 46 b, and to second member 14 through the use of tethers 46 c and 46d. Likewise, second wedge 18 is attached to first member 12 through theuse of tethers 48 a and 48 b, and to second member 14 through the use oftethers 48 c and 48 d. Of course, any number of tethers may be utilizedin connecting the wedges to the first and second members. Tethers 46 a-dand 48 a-d are preferably deformable so as to allow the movement offirst and second wedges 16 and 18 with respect to first and secondmembers 12 and 14. As is shown in the figures, the tethers may employ ashape that allows them to deform in a proper fashion upon movement offirst and second wedges 16 and 18 with respect to first and secondmembers 12 and 14. Like struts 20 a-d, tethers 46 a-d and 48 a-dincorporate a structure specifically designed to allow for an even andconsistent deployment of implant 10. Specifically, each tether includesan end section 110 (best shown in connection with the illustration oftethers 46 a, 46 c, 48 a, and 48 c in FIG. 5) at the connection betweenthe tether and one of first or second members 12 or 14, which is thickerthan other areas of the tether to limit deformation. In addition, thissection 110 is shaped in the manner shown in order to force a thinnercurved tether section 112 to deform toward either the first or secondmember during the initial expansion of implant 10. This specificgeometry results in the tether's initial movement to be a collapsingmotion at section 110. Furthermore, each of tethers 46 a-d and 48 a-dinclude a connection section 114 at the connection between the tetherand one of first or second wedges 16 or 18. This section, like section110, is thicker than section 112 to limit the amount of deformation atthe coupling of the tether and the wedge. The final expanded state ofimplant 10 is best shown in FIG. 6, which illustrates the final positionof the tethers.

In order to be suitable for implantation into the human body, all of theelements of implant 10 are preferably biocompatible. For example, in apreferred embodiment, each of the components of implant 10 isconstructed of a metal, such as titanium (commercially pure grade 2).However, other biocompatible materials may be utilized, like othertitaniums, PEEK, titanium/PEEK composites, nitonol, bioresorbables, andthe like. Depending upon the material utilized, certain of thecomponents may be formed integral with or separately from one another.For example, struts 20 a-d, in certain embodiments, may be formedintegral with first and second members 12 and 14. Of course, in otherembodiments, struts 20 a-d and first and second members 12 and 14 may beformed separately and constructed together in accordance with normalpractices. For instance, these portions could be welded or otherwisefused together.

Implant 10 also preferably includes certain elements which cooperate tosubstantially prevent torsional movement of the first and second wedges16 and 18 with respect to first and second members 12 and 14. Of course,such elements are not required for proper operation of the device. As isshown in FIGS. 1-6, first and second members 12 and 14 are provided withelongate protuberances (50 a-d and 52 a-d, respectively). Theseprotuberances preferably extend somewhat below the angled interiorsurfaces of first and second members 12 and 14, respectively. First andsecond wedges 16 and 18, on the other hand, each include four channelsfor cooperation with the protuberances. Specifically, first wedgeincludes channels 54 a-d and second wedge includes channels 56 a-d.

The cooperation between the above-discussed protuberances and channelsis such that movement of wedges 16 and 18 with respect to each other andfirst and second members 12 and 14 is not inhibited (i.e., the wedgescan move in similar directions as depicted by arrows A and B of FIG. 5).However, any torsional or rotational movement of the wedges with respectto the first and second members is prevented. In other words, first andsecond wedges 16 and 18 are prevented from going off track. This is animportant feature in ensuring a consistent operation of implant 10.

In operation, movement of first wedge 16 in the direction of arrow A(FIG. 5) and movement of second wedge 18 in the direction of arrow B(also FIG. 5), causes first and second members 12 and 14 to move awayfrom one another. In other words, movement of first and second wedges 16and 18 towards one another causes the expansion of implant 10. Movementof first and second wedges 16 and 18 can be achieved through the use ofa deployment tool (discussed below). At least a portion of such a toolpreferably passes through second wedge aperture 44 of second wedge 18,through an interior of implant 10 defined by first and second members 12and 14 and struts 20 a-d, and into engagement with first wedge aperture42. In certain embodiments, first wedge aperture 42 is threaded so as toallow for threadable engagement of the tool to the first wedge. However,other connections may also be utilized. As is discussed more fullybelow, deployment tool preferably acts so as to apply a pushing force tosecond wedge 18 while at the same time applying a pulling force to firstwedge 16. This causes the necessary movement of the first and secondwedges 16 and 18 towards one another.

The deformable nature of tethers 46 a-d and 48 a-d allows them to followalong with first and second wedges 16 and 18 during their movementtowards one another. So, at all times the wedges are connected to firstand second members 12 and 14, thereby preventing them from becomingdislodged from implant 10. This is an important safety feature of theimplant. Furthermore, the above-discussed teeth located on the first andsecond angled interior surfaces and the angled wedge surfaces allows forthe movement of first and second wedges 16 and 18 in the direction ofarrows A and B, respectively, but prevents opposite movement of thecomponents. In other words, the different cooperating teeth (i.e., 27 aand 37 a, 27 b and 39 a, 33 a and 37 b, and 33 b and 39 b) are designedso as to allow the first movement, but prevent the second, oppositemovement. Many different teeth designs can be employed in order toachieve this functionality.

FIGS. 13-19 depict an impaction instrument 310. This instrument ispreferably utilized by a surgeon or other medical professional in orderto initially place the implant between two adjacent vertebral bodies.Because of the nature of a damaged intervertebral disc space (i.e., in acollapsed position), even the nonexpanded state of implant 10 may beslightly larger than the space between adjacent vertebral bodies. Thus,an impaction instrument, like instrument 310, often must be utilized ininitially placing implant 10 in position. As is shown in FIGS. 13-19,instrument 310 includes three separate components, a tapered rod 312, asleeve 314, and a locking knob 316. Tapered rod 312 is preferablythreaded at its distal end 318 in order to couple with a portion ofimplant 10. In other embodiments, different coupling mechanisms may beemployed. Sleeve 314 preferably includes a pair of deformable fingers320 a and 320 b, which are capable of expanding outwardly upon insertionof sleeve 314 over the tapered portion 322 of tapered rod 312. Thisexpanded state is best shown in FIGS. 13-15.

In use of instrument 310, a surgeon would first couple tapered rod 312with implant 10, by passing distal end 318 of the rod through aperture44 in the wedge 18 and into contact with aperture 42 of first wedge 16.At this time, the threadable connection can be made by simply threadingdistal portion into aperture 42. The general coupling of rod 312 withimplant 10 is best shown in FIG. 16, while FIG. 18 depicts thethreadable coupling of the distal end of rod 312 with aperture 42 offirst wedge 16. Once the position shown in FIG. 16 is achieved, asurgeon or other medical professional then preferably slides sleeve 314over tapered rod 12, thereby expanding fingers 320 a and 320 b. Thisstate is best shown in FIG. 17. As is shown in the cross sectional viewof FIG. 18, fingers 320 a and 320 b contact a portion of each of firstand second members 12 and 14. In addition, as sleeve rod 314 is insertedover tapered rod 312, a shoulder portion 324 of such is engaged with anexterior portion of second wedge 18. At the same time, distal end 318 ofrod 312 is engaged with aperture 42 of wedge 16 and a shoulder portion325 of rod 312 is in contact with a surface of wedge 16. In thisposition, locking knob 316 is then tightened down on the proximal end326 of instrument 310, thereby locking rod 312 and sleeve 314 inposition. Implant 10 is now protected for insertion through impaction,as first and second members 12 and 14, and wedges 16 and 18 are lockedin position and cannot move with respect to each other or any othercomponent of this assembly. A hammer or other impaction instrument canbe utilized to apply a force to a back portion 328 (best shown in FIG.19) of locking knob 316 in order to push implant 10 into theintervertebral disc space. In this regard, it is to be understood thatportion 328 may be provided with a coating or other material suitable toaccept the shock provided by the force from a hammer or the like.

FIG. 20 shows a sample deployment tool 350. As is mentioned above, suchtool includes a distal portion 352 (shown being disposed within implant10) capable of passing through aperture 44 of second wedge 18 and intoengagement with aperture 42 of first wedge 16. In addition, tool 350also includes a portion 354 capable of engagement with second wedge 18.Upon actuation of a trigger 356, first portion 352 and second portion354 move toward one another, thereby pushing wedges 16 and 18 toward oneanother. This movement of first and second portion 352 and 354 towardsone another is facilitated by an actuation mechanism 358 associated withtrigger 356. As is more fully discussed above, this movement leads tothe expansion of implant 10. Although the embodiment shown includes afirst portion, which is designed to threadably connect with aperture 42,other connections are clearly contemplated.

During a surgical procedure, a surgeon would preferably insert anunexpanded implant 10 into the space between two adjacent vertebra,utilizing the above-discussed impaction instrument 310. This space wouldpreferably first be cleared so as to provide the space necessary toreceive the implant. The angled, bulleted, or rounded exterior surfaceof first wedge 16 is preferably first inserted thereby aiding in thecomplete insertion of implant 10. These surfaces essentially makeinsertion easier, and may facilitate a slight distraction of theadjacent vertebra in order to allow for acceptance of implant 10 intothe space. Impaction instrument 310 preferably holds the variouscomponents of implant 10 in a locked position throughout the insertion.Once fully inserted between the adjacent vertebrae, deployment tool 350may be engaged with implant 10. It is to be understood that whileinsertion and deployments of the implant can be achieved through the useof two different tools, it is also possible to utilize a single tool forboth steps. For example, a combination impaction and deployment tool(not shown) could be provided and engaged with implant 10 prior toinsertion and left attached throughout deployment.

Upon movement of first and second wedges 16 and 18 towards one another,first and second members 12 and 14 expand, which preferably acts to bothdistract the vertebral space and also dig projections 23 and 29 of thevertebral contact surfaces 22 and 28 into the vertebral end plates ofthe vertebra they are in contact with. As is mentioned above, thedifferent cooperating teeth (i.e., 27 a and 37 a, 27 b and 39 a, 33 aand 37 b, and 33 b and 39 b) allow for the expansion of implant 10, butprevent its contraction. Thus, once expanded, implant 10 remains in sucha state without the addition of any further components. Nonetheless, oneor more locking components could be utilized to ensure that implant 10remains in the expanded state.

It is to be understood that the above brief discussion of the surgicalprocedure associated with the present invention is merely exemplary, andmore, less, or different steps may be performed. Moreover, it is to beunderstood that more than one implant 10 may be inserted and deployedbetween adjacent vertebrae. Depending upon the overall size of theimplant (which may widely vary), more than one implant may be requiredin order to properly support the disc space. With the implant(s) inplace and deployed, the disc space is preferably restored to at or nearits original height. Bone growth may preferably occur through apertures34 and 36 of the first and second members 12 and 14, respectively. It isnoted that first and second wedges 12 and 14 may include similarapertures or voids which ensure an open passage through implant 10 uponfull expansion. In the expanded state, the interior of implant 10 can bepacked with bone morphonogenic proteins or other bone growth inducingsubstances in order to encourage this bone growth from one adjacentvertebra to the other.

FIGS. 7-9 depict a second embodiment implant 110. Essentially, implant110 is substantially similar to implant save for the inclusion ofdifferent torsion inhibiting elements. Because of the similarity ofimplant 110 with implant 10, similar or identical elements will bereferred to with like reference numerals within the 100-series ofnumbers. For example, implant 110 includes first and second members 112and 114 which are expandable upon movement of first and second wedges114 and 116 towards one another. However, in the embodiment shown inFIGS. 7-9, first and second members 112 and 114 are provided withapertures (150 a-d and 152 a-d, respectively) which are capable ofreceiving protuberances (not shown). For example, these apertures mayreceive pins, screws, or plugs which extend somewhat below the angledinterior surfaces of first and second members 112 and 114, respectively.First and second wedges 116 and 118, on the other hand, each includefour channels for cooperation with the protuberances. Specifically,first wedge includes channels 154 a-d and second wedge includes channels156 a-d.

The cooperation between the protuberances and channels is like that thatsimilar elements of implant 10 such that movement of wedges 116 and 118with respect to each other and first and second members 112 and 114 isnot inhibited. However, any torsional or rotational movement of thewedges with respect to the first and second members is prevented. Inother words, first and second wedges 116 and 118 are prevented fromgoing off track.

FIGS. 10-12 depict yet another embodiment implant 210. Like, implant110, implant 210 is similar to implant 10, save for the inclusion ofdifferent torsion inhibiting elements. Once again, like elements inimplant 210 will be referred to within the 200-series of numbers.Instead of including a series of channels and protuberances, the torsioninhibiting elements of implant 210 include a tongue and groovecooperation between its first and second members 212 and 214 and itsfirst and second wedges 216 and 218. Specifically, first wedge 216 isprovided with a first tongue 250 a for cooperation with a first groove252 a of the first member, and a second tongue 250 b for cooperationwith a second groove 252 b of the first member. Likewise, second wedge218 is provided with a first tongue 250 c for cooperation with a firstgroove 252 c of the first member, and a second tongue 250 d forcooperation with a second groove 252 d of the second member. Theseelements cooperate in order to provide a nearly identical function tothat of the torsion inhibiting elements discussed above in connectionwith implant 110. It is to be understood that each of the abovediscussed torsion inhibiting elements may vary. For instance, thespecific shapes of the elements can widely vary. Moreover, the inclusionof certain elements on certain components may be swapped. For example,implant 210 may include wedges employing grooves and first and secondmembers employing tongues.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

1. A method of inserting a spinal implant an intervertebral disc spacecomprising the steps of: providing an expandable implant forimplantation between two vertebral bodies including first and secondmembers and first and second wedges; coupling a rod to the first wedgeof the expandable implant; placing a sleeve having deformable fingersover the rod whereby the deformable fingers contact the first and secondmembers of the expandable implant; and attaching a locking knob to therod and the sleeve to fix the rod and the sleeve with respect to eachother.
 2. The method of inserting a spinal implant of claim 1, whereinthe step of coupling the rod to the first wedge of the expandableimplant includes inserting the rod through an aperture formed in thesecond wedge aperture and threading a distal portion of the rod into athreaded aperture of the first wedge.
 3. The method of inserting aspinal implant of claim 2, wherein the placing step includes expandingthe deformable fingers of the sleeve.
 4. The method of inserting aspinal implant of claim 1, wherein the rod includes a rod shoulder andthe tapered portion, the step of coupling the rod to the first wedge ofthe expandable implant including placing the rod shoulder in contactwith the first wedge.
 5. The method of inserting a spinal implant ofclaim 4, wherein the sleeve includes a sleeve shoulder, the step ofsliding the sleeve including placing the sleeve shoulder in contact withthe second wedge.
 6. The method of inserting a spinal implant of claim4, wherein the tapered portion of the rod expands the deformable fingersof the sleeve.
 7. The method of inserting a spinal implant of claim 1,further comprising the step of utilizing a hammer to apply an impactionforce to the locking knob to push the expandable implant into theintervertebral disc space.
 8. The method of inserting a spinal implantof claim 7, wherein the locking knob has a back portion having a coatingto accept the shock provided by the hammer.